"Doom 3 is a very resource intensive game. If you’re not particularly willing to upgrade your hardware to improve performance, then some of our previous Tweak Guides will aid you in getting the most out of what you’ve already got.

Finally, before using any of the settings covered here be sure to enter the Options menu, select System, select Scan Hardware and Select Optimal Video Quality. This sets up many of the necessary options you will need to run the game correctly and it would be worth doing so again should you change Graphics card also."